Lubrication plug

ABSTRACT

In an off-highway vehicle having an electric propulsion system which includes a motorized wheel, a traction motor and a transmission for transmitting power from the traction motor to the motorized wheel, wherein the transmission comprises a reduction stage, a low speed sun pinion defining a sun pinion cavity and a thrust washer, wherein the thrust washer includes a first surface portion movably associated with the low speed sun pinion via a thrust washer retainer and wherein the thrust washer is movably associated with the reduction stage via a lubrication plug is provided, wherein the lubrication plug includes a first plug portion having a radially extending portion movably associated with a second surface portion of the thrust washer and a second plug portion having a second plug portion structure which defines a plug cavity having a plug cavity inlet and at least one plug cavity outlet disposed adjacent at least a portion of the thrust washer, wherein the plug cavity inlet is disposed to communicate the sun pinion cavity with the plug cavity and wherein the at least one plug cavity outlet is disposed along at least one radial plane of the second plug portion to communicate the plug cavity with the thrust washer, such that a lubricant flowing through the sun pinion cavity and into the plug cavity inlet is allowed to flow out of the at least one plug cavity outlet such that the lubricant and the thrust washer lubricatingly interact.

RELATED APPLICATIONS

This application is a Continuation-In-Part of U.S. patent applicationSer. No. 11/056,989 filed Feb. 11, 2005 entitled “Sun Pinion Cover”, andclaims priority from co-pending U.S. patent application Ser. No.11/056,989 filed Feb. 11, 2005 entitled “Sun Pinion Cover” and PCTApplication No. PCT/US05/15589 filed May 4, 2005 entitled “ImprovedLubrication in a Transmission,” both of which depend from U.S.Provisional Patent Application Ser. No. 60/568,377 filed May 5, 2004,the contents of both of which are incorporated herein by reference intheir entireties.

FIELD OF THE INVENTION

The present invention relates generally to the lubrication of atransmission and more particularly to an improved lubrication plug foran electric mining truck transmission.

BACKGROUND OF THE INVENTION

Large off-road, heavy-duty work vehicles, such as mining vehicles usedto haul heavy payloads excavated from open pit mines, are well known andusually employ motorized wheels for propelling or retarding the vehiclein an energy efficient manner. This type of vehicle is shown in FIG. 1.This efficiency is typically accomplished by employing a largehorsepower diesel engine in conjunction with an alternator and a maintraction inverter. The diesel engine is directly associated with thealternator such that the diesel engine drives the alternator. Thealternator is used to power the main traction inverter, wherein the maintraction inverter supplies power having a controlled voltage andfrequency to two drive or traction motors connected to the rear wheelsof the vehicle. The motors may be either AC or DC operated. As eachdrive motor is operated, the drive motor causes a transmission driveshaft to rotate at a low torque and high speed about the drive shaftaxis. Because the transmission drive shaft is directly associated withthe vehicle transmission, the low torque high speed rotational energy ofthe transmission drive shaft is communicated to the vehicletransmission. The vehicle transmission then takes the low torque highspeed rotational energy supplied by the transmission drive shaft andconverts this energy into a high torque low speed rotational energyoutput which is supplied to the rear wheels.

Referring to FIG. 2, the conversion of this low torque high speedrotational energy into a high torque low speed rotational energy istypically accomplished using a double reduction gear set disposed withinthe vehicle transmission. A double reduction gear set is a series ofgears, pinions and planets that includes a first reduction stage and asecond reduction stage. The first reduction stage may include ahigh-speed sun pinion, a plurality of high-speed planets and astationary ring gear and the second reduction stage may include alow-speed sun pinion, a plurality of low-speed planets and a stationaryring gear. The output of the first reduction stage is connected to theinput of the second reduction stage and may be referred to as thehigh-speed carrier. In a similar manner, the output of the secondreduction stage is connected to the vehicle wheels via a torque tube/hubassembly. Inward and outward thrust washers on the low-speed pinion actto enable rotation of the low-speed pinion relative to the high-speedpinion and the transmission housing, locate the high speed carrierwithin the transmission and to counter act any movement of the highspeed carrier while reducing friction.

As described above, a transmission of this type includes a plurality ofmoving parts that interact and mesh with each other in order to convertthe low torque high-speed energy into high torque low-speed energy. Assuch, it is essential to keep all of the parts of the transmission welllubricated to avoid undue wear and equipment failure. Currently, thecomponents within the transmission are lubricated using a “splash”process. This “splash” process involves partially filling the torquetube/hub assembly with oil such that the lubrication is distributed tothe transmission components during movement of the high-speed carrier,the low-speed carrier, the high-speed planets and the low-speed planets.As these components move, the lubricating oil contained within thetorque tube that has adhered to these components splashes from thecarriers onto the components contained in the transmission, such as thelow-speed sun pinion. As the low-speed sun pinion and the high-speedplanets mesh together, the oil that adheres to both gears during the“splash” process gets squeezed out of the mesh in the axial direction ofthe transmission, providing lubrication to additional parts of thetransmission. This provides adequate lubrication to the radial outersurfaces of the thrust washers, but does not allow for adequatelubrication to the radial inner surfaces.

Although the above lubrication process provides for sufficientlubrication of all of the internal parts of the transmission, includingkey wear components, any additional oil flow to critical areas of thetransmission would be advantageous and may provide an additional marginof safety for those wheels that may be subjected to additional loads dueto application and/or working environment. This additional margin ofsafety is desirable as an additional precaution to prevent the need forfrequent replacement of equipment parts and/or catastrophic failure ofthe equipment.

SUMMARY OF THE INVENTION

In an off-highway vehicle having an electric propulsion system, whereinthe electric propulsion system includes a motorized wheel, a tractionmotor for delivering power to the motorized wheel and a transmission fortransmitting power from the traction motor to the motorized wheel,wherein the transmission comprises a reduction stage, a low speed sunpinion defining a sun pinion cavity, and a thrust washer, wherein thethrust washer includes a first surface portion movably associated withthe low speed sun pinion via a thrust washer retainer and wherein thethrust washer is movably associated with the reduction stage via alubrication plug, the lubrication plug comprising: a first plug portion,wherein said first plug portion includes a radially extending portionmovably associated with a second surface portion of the thrust washer;and a second plug portion having a second plug portion structure,wherein said second plug portion structure defines a plug cavity havinga plug cavity inlet and at least one plug cavity outlet disposedadjacent at least a portion of the thrust washer, wherein said plugcavity inlet is disposed to communicate the sun pinion cavity with saidplug cavity and wherein said at least one plug cavity outlet is disposedalong at least one radial plane of said second plug portion tocommunicate said plug cavity with the thrust washer, such that alubricant flowing through the sun pinion cavity and into said plugcavity inlet is allowed to flow out of said at least one plug cavityoutlet such that said lubricant and the thrust washer lubricatinglyinteract.

A transmission assembly, comprising: a hub assembly, wherein said hubassembly defines a hub assembly cavity and a transmission opening, saidtransmission opening being communicated with said hub assembly cavity; asun pinion, wherein said sun pinion defines a sun pinion cavity andincludes a thrust washer retainer and wherein said sun pinion isdisposed within said hub assembly cavity such that said transmissionopening is further communicated with said sun pinion cavity; and areduction stage having a lubrication plug, wherein said lubrication plugis movably associated with said thrust washer retainer via a thrustwasher having a first surface portion and a second surface portion, saidlubrication plug including, a first plug portion, wherein said firstplug portion includes a radially extending portion movably associatedwith a second surface portion; and a second plug portion, wherein saidsecond plug portion defines a plug cavity having a plug cavity inlet andat least one plug cavity outlet, wherein said plug cavity inlet isdisposed to communicate said sun pinion cavity with said plug cavity andwherein said at least one plug cavity outlet is disposed along at leastone radial plane of said second plug portion to communicate said plugcavity with said thrust washer, such that a lubricant flowing throughsaid sun pinion cavity and into said plug cavity inlet is allowed toflow out of said at least one plug cavity outlet such that saidlubricant and the thrust washer lubricatingly interact.

A method for increasing lubricant flow within an electric-motor driven,off-highway vehicle transmission, wherein the transmission includes areduction stage, a low-speed sun pinion defining a sun pinion cavity anda thrust washer to enable relative rotation of the low-speed sun pinionand the reduction stage, wherein the thrust washer is movably associatedwith the sun pinion via a thrust washer retainer and wherein the thrustwasher is movably associated with the reduction stage via a lubricationplug which is communicated with the sun pinion cavity, the methodcomprising: forming a lubricant conduction path between the sun pinioncavity and the thrust washer; and directing a lubricant to flow betweenthe sun pinion cavity and the thrust washer via said lubricantconduction path to deliver lubricant to the thrust washer.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The foregoing and other features and advantages of the present inventionwill be more fully understood from the following detailed description ofillustrative embodiments, taken in conjunction with the accompanyingdrawings in which like elements are numbered alike in the severalFigures:

FIG. 1 is a side perspective view of an off-road, heavy-duty workvehicle of the type that uses an AC transmission;

FIG. 2 is a cross sectional side view of a transmission having a sunpinion cover, in accordance with the prior art;

FIG. 3 is a cross sectional side view of a sun pinion cover, inaccordance with a preferred embodiment;

FIG. 4 is a side cutout view of a transmission employing the sun pinioncover of FIG. 3;

FIG. 5 is a side cutout view of a Transmission employing the sun pinioncover of FIG. 3;

FIG. 6 is an additional side perspective view of an off-road, heavy-dutywork vehicle of the type that uses a transmission;

FIG. 7 is a cross sectional side view of a sun pinion cover, inaccordance with a second embodiment;

FIG. 8 is a cross sectional side view of a sun pinion cover, inaccordance with a third embodiment;

FIG. 9 is a cross sectional side view of a lubrication plug inaccordance with an exemplary embodiment;

FIG. 10 is a front perspective view of a thrust washer for use with thelubrication plug of FIG. 9;

FIG. 11 is a cross sectional side view of the lubrication plug of FIG.10 associated with the thrust washer of FIG. 11 and the transmission ofFIG. 5;

FIG. 12A is a front view of the lubrication plug of FIG. 9;

FIG. 12B is a front view of the lubrication plug of FIG. 9;

FIG. 13 is a block diagram illustrating a method for increasinglubricant flow within an electric-motor driven, in accordance with anexemplary embodiment;

FIG. 14 is a side cutout view of the transmission of FIG. 5 employingthe sun pinion cover of FIG. 3 and the lubrication plug of FIG. 9; and

FIG. 15 is a cross sectional side view of a lubrication plug, inaccordance with a first alternative embodiment;

FIG. 16 is a cross sectional side view of a lubrication plug, inaccordance with a second alternative embodiment;

FIG. 17 is a front view of the lubrication plug of FIG. 16; and

FIG. 18 is a cross sectional side view of the lubrication plug of FIG.16 associated with the thrust washer of FIG. 11 and the transmission ofFIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 3, a sun pinion cover 100 is illustrated and includesa cover body structure 102 having a cover outer surface 104 and a coverinner surface 106. Cover inner surface 106 defines a lubricant inletport 108 and a lubricant outlet port 110, wherein lubricant inlet port108 is communicated with lubricant outlet port 110 via a lubricantconduction channel 112. Sun pinion cover 100 also defines at least onesuitable fastener engagement hole, such as a bolt hole, 114 disposed toallow sun pinion cover 100 to be detachably secured to a transmissionassembly hub.

Referring to FIG. 4 and FIG. 5, a sun pinion cover 100 is showndetachably secured with a transmission 116. Transmission 116 includes ahub assembly 118, which defines at least one hub mounting cavity 120, atransmission opening 122 and a hub assembly cavity 124, whereintransmission opening 122 is communicated with hub assembly cavity 124.Transmission 116 also includes a double reduction gear set 126 disposedwithin hub assembly cavity 124, wherein double reduction gear set 126includes a stationary ring gear 128, a first reduction stage 130 and asecond reduction stage 132. First reduction stage 130 includes ahigh-speed sun pinion 134, a plurality of high-speed planets 136 and ahigh-speed carrier 138, wherein high-speed carrier 138 transmits theoutput of first reduction stage 130 to second reduction stage 132.High-speed carrier 138 is disposed within transmission 116 such that itsaxial motion is restrained by an outboard thrust washer 140 riding onthe cover inner surface 106 and an inboard thrust washer 142 riding on aplug 144.

Second reduction stage 132 includes a low-speed sun pinion 146, aplurality of low-speed planets 148 and a low-speed carrier 150, whereinlow-speed sun pinion 146 is the input to second reduction stage 132 andreceives the output of first reduction stage 130 from high-speed carrier138. Low-speed carrier 150 receives the output of second reduction stage132 and transmits this high torque output to the vehicle wheels. Sunpinion cover 100 is shown non-movably associated with hub assembly 118via at least one mounting device 152 such that sun pinion cover 100 isdisposed over transmission opening 122 to sealingly enclose hub assemblycavity 124. Moreover, sun pinion cover 100 is disposed relative to hubassembly 118 such that lubricant inlet port 108 is adjacent theplurality of low-speed planets 148 and such that lubricant outlet port110 is adjacent low-speed sun pinion 146. This allows lubricant to flowbetween plurality of low-speed planets 148 and low-speed sun pinion 146via lubricant conduction channel 112. The cover 100 may include two ormore channels 112 at spaced intervals around the cover 100. Whilechannel 112 is shown as being spaced from the inner surface 106 of thecover 100 to present a passage open only at ends of inlet 108 and outlet110, the channel may alternatively be formed as a recess in the innersurface 106 of the cover 100 extending between the inlet 108 and theoutlet 110.

Referring to FIG. 4, FIG. 5 and FIG. 6, an off-road, heavy-duty workvehicle 154 is shown and includes a large horsepower diesel engine 158coupled to an alternator 160, a main traction inverter 162, at least oneAC drive motor 164 and a transmission drive shaft 166. As the vehicle154 is operated, diesel engine 158 drives alternator 160 to power maintraction inverter 162. Main traction inverter 162 supplies power to ACdrive motor 164, wherein main traction inverter 162 controls the voltageand frequency of the power supplied to AC drive motor 164. AC drivemotor 164 converts this electrical energy into mechanical energy bycausing transmission drive shaft 166 to rotate in relation to the powersupplied to AC drive motor 164. The rotation of transmission drive shaft166, which communicates AC drive motor 164 with high-speed sun pinion134, transfers the mechanical energy from AC drive motor 164 to ACtransmission 116.

As briefly discussed above, high-speed sun pinion 134 is part of firstreduction stage 130. As such, because the rotation of transmission driveshaft 166 causes high-speed sun pinion 134 to rotate, the high-speed lowtorque mechanical energy from AC drive motor 164 is transferred intofirst reduction stage 130 via high-speed sun pinion 134. This high-speedlow torque rotational energy is converted into lower-speed higher torqueenergy via first reduction stage 130 and transferred to second reductionstage 132 via low-speed sun pinion 146. The converted energy from firstreduction stage 130 is converted further into low-speed high torqueenergy via second reduction stage 132. At this point, the low-speed hightorque energy is transferred to the vehicle wheels via low-speed carrier150. As the high-speed low torque energy received by AC transmission 116is being converted into low-speed high torque energy, the componentswithin AC transmission 116 are rapidly moving and interacting with eachother.

When low-speed sun pinion 146 and low-speed planets 148 interact andmesh together, the lubricant that adheres to low-speed sun pinion 146and low-speed planets 148 is compressed out of the mesh in the axialdirection toward sun pinion cover 100. Because lubricant inlet port 108is adjacent low-speed planets 148, the meshing of the low-speed planetsand the sun-pinion provides a pumping action for directing lubricantinto lubricant inlet port 108, through lubricant duct 112, out oflubricant outlet port 110 and into the central passage of low-speed sunpinion 146. This provides a continuous lubricant flow through thecentral passage of low-speed sun pinion 146 thus providing lubricationto outboard thrust washer 140 and inboard thrust washer 142. Lubricantflow to the inward and outward thrust washers thereby assureslubrication at the radial inner surfaces of these critical wearcomponents for extending their useful lives.

Referring to FIG. 7, a second embodiment of sun pinion cover 200 isshown and includes a plurality of lubricant inlet ports 208, a pluralityof lubricant outlet ports 210 and a plurality of lubricant ducts 212,wherein each of the plurality of lubricant inlet ports 108 arecommunicated with at least one of the plurality of lubricant outletports 210 via the plurality of lubricant ducts 212. Moreover, referringto FIG. 8, a third embodiment of sun pinion cover 300 is shown andincludes a first lubricant inlet port 308, a second lubricant inlet port309, a first lubricant outlet port 310 and a second lubricant outletport 311, wherein the first lubricant inlet port 308 is communicatedwith the first lubricant outlet port 310 via a first lubricant duct 312and wherein the second lubricant inlet port 309 is communicated with thesecond lubricant outlet port 311 via a second lubricant duct 313. Itshould be appreciated that a directional flow valve may be included anddisposed to be communicated with the lubrication duct to control thedirection of lubricant flow through the lubrication duct. Moreover, itshould also be appreciated that although the sun pinion cover 100 isdescribed herein as being associated with an AC transmission 116 havingdouble reduction gear set 126, it should be appreciated that sun pinioncover 100 may be used with any type of transmission suitable to thedesired end purpose.

Referring to FIG. 9, a cross-sectional side view of a lubrication plug900 is shown and includes a first plug portion 902 and a second plugportion 904. The first plug portion 902 includes a radially extendingportion 906 having an extending portion inboard surface 908 and anextending portion outboard surface 910, wherein the lubrication plug 900is non-movably associated with the reduction gear set 126 via any methodsuitable to the desired end purpose, such as a press fit. The secondplug portion 904 includes a second plug portion structure 914 whichextends away from the radially extending portion 906 and which defines aplug cavity 916 having at least one plug cavity inlet 918 and at leastone plug cavity outlet 920, wherein the at least one plug cavity outlet920 is communicated with the at least one plug cavity inlet 918 via theplug cavity 916. It should be appreciated that the at least one plugcavity outlet 920 includes at least one inboard plug cavity outlet 922disposed along a first radial plane R₁ of the second plug portion 904and at least one outboard plug cavity outlet 924 disposed along a secondradial plane R₂ of the second plug portion 904.

Referring to FIG. 10, a front perspective view of the inboard thrustwasher 142 is shown, wherein the inboard thrust washer 142 includes aninboard thrust washer structure 926 which defines an inboard thrustwasher cavity 928 and includes a first thrust washer surface 930 and asecond thrust washer surface 932. Referring to FIG. 11, a crosssectional side view of the lubrication plug 900 is shown disposed withinthe transmission 116 to be associated with the reduction gear set 126and the inboard thrust washer 142. The lubrication plug 900 may beassociated with the reduction gear set 126 via any method and/or devicesuitable to the desired end purpose, such as being press fit together tofrictionally interact together. The inboard thrust washer 142 is movablyassociated with the lubrication plug 900 such that at least a portion ofthe second plug portion 904 is disposed within the inboard thrust washercavity 928 and such that the first thrust washer surface 930 of theinboard thrust washer 142 is adjacent to the extending portion outboardsurface 910 of the radially extending portion 906. Additionally, theinboard thrust washer 142 is movably associated with the low speed sunpinion 146 via a thrust washer retainer 936 such that the second thrustwasher surface 932 of the inboard thrust washer 142 is adjacent thethrust washer retainer 936, wherein the low speed sun pinion 146 definesa sun pinion cavity 938. It should be appreciated that when lubricationplug 900 and the inboard thrust washer 142 are associated with thetransmission 116, the inboard thrust washer 142 is disposed such thatthe first thrust washer surface 930 is adjacent the inboard plug cavityoutlet 922 and the second thrust washer surface 932 is adjacent theoutboard plug cavity outlet 924. This allows a lubricant to flow betweenthe sun pinion cavity 938 and the first thrust washer surface 930 andthe second thrust washer surface 932 via the lubrication plug cavity916.

Referring to FIG. 12A, the at least one inboard plug cavity outlet 922may include a first plug interface outlet 942, a second plug interfaceoutlet 944, a third plug interface outlet 946 and a fourth pluginterface outlet 948, each of which are disposed radially along thefirst radial plane R₂ of the second plug portion 904. The first pluginterface outlet 942 may be disposed at an angle σ₁ from the second pluginterface outlet 944 and an angle σ₂ from the fourth plug interfaceoutlet 948. The third plug interface outlet 946 may be disposed at anangle σ₃ from the second plug interface outlet 944 and an angle σ₄ fromthe fourth plug interface outlet 948. Moreover, the first plug interfaceoutlet 942 may be disposed at an angle σ₅ from the third plug interfaceoutlet 946 and the second plug interface outlet 944 may be disposed atan angle σ₆ from the fourth plug interface outlet 948.

In a similar fashion referring to FIG. 12B, the at least one outboardplug cavity outlet 924 may include a first retainer interface outlet950, a second retainer interface outlet 952, a third retainer interfaceoutlet 954 and a fourth retainer interface outlet 956 each of which aredisposed radially along the second radial plane R₁ of the first plugportion 902. As above, the first retainer interface outlet 950 may bedisposed at an angle β₁ from the second retainer interface outlet 952and an angle β₂ from the fourth retainer interface outlet 956, the thirdretainer interface outlet 954 may be disposed at an angle β₃ from thesecond retainer interface outlet 952 and an angle β₄ from the fourthretainer interface outlet 956, the first retainer interface outlet 950may be disposed at an angle β₅ from the third retainer interface outlet954 and the second retainer interface outlet 952 may be disposed at anangle β₆ from the fourth retainer interface outlet 956. Moreover,referring to FIGS. 12A and 12B, the at least one inboard plug cavityoutlet 922 may be disposed to be radially offset by an angle μ relativeto the at least one outboard plug cavity outlet 924.

Referring to FIG. 13, a block diagram illustrating a method 958 forincreasing lubricant flow 952 within an electric-motor driven,off-highway vehicle transmission 116 is shown, wherein the transmission116 includes a reduction stage 126, a low-speed sun pinion 146 defininga sun pinion cavity 938 and an inboard thrust washer 142 to enablerelative rotation of the low-speed sun pinion 146 and the reductionstage 126. The inboard thrust washer 142 is movably associated with thelow-speed sun pinion 146 via a thrust washer retainer 936 and whereinthe inboard thrust washer 142 is movably associated with the reductionstage 126 via the lubrication plug 900 which is communicated with thesun pinion cavity 938. The method 958 includes forming a lubricantconduction path 952 between the sun pinion cavity 938 and the inboardthrust washer 142, as shown in operational block 960, and directing alubricant to flow between the sun pinion cavity 938 and the thrustwasher 142 via the lubricant conduction path to deliver lubricant to thethrust washer 142, as shown in operational block 962. This may beaccomplished by modifying the lubrication plug 900 to define a plugcavity 916 having a plug inlet 918 and at least one plug outlet 920,wherein the plug inlet 918 is disposed to be communicated with the sunpinion cavity 938 and wherein the at least one plug outlet 920 isdisposed to be communicated with at least a portion of the thrust washer142. The plug cavity 916, which may be defined by the lubrication plug900, is shown as being disposed to be communicated with the sun pinioncavity 938, wherein the plug cavity 916 includes the inboard plug cavityoutlet 922 and the outboard plug cavity outlet 924.

Referring to FIG. 14, the transmission 116 is shown having the sunpinion cover 100 and the lubrication plug 900. As the transmission 116is operated, the low-speed sun pinion 146 and the low-speed planets 148interact and mesh together. This causes the lubricant 964 that adheresto the low-speed sun pinion 146 and the low-speed planets 148 to becompressed out of the mesh in the axial direction toward the sun pinioncover 100. Because the lubricant inlet port 108 is adjacent thelow-speed planets 148, the meshing of the low-speed planets 148 and thelow-speed sun pinion 146 provides a pumping action for directing thelubricant 964 into the lubricant inlet port 108, through the lubricantduct 112, out of the lubricant outlet port 110 and into the sun pinioncavity 938 of the low-speed sun pinion 146. This directs a continuouslubricant flow 940 into and through the sun pinion cavity 938 to providelubrication to the outboard thrust washer 140. The continuous lubricantflow 966 also directs the lubricant 964 through the plug cavity inlet918, into the plug cavity 916 and out of the at least one inboard plugcavity outlet 922 and the at least one outboard plug cavity outlet 924to lubricantly interact with at least one of the first thrust washersurface 930 and the second thrust washer surface 932.

Although the at least one inboard plug cavity outlet 922 and the atleast one outboard plug cavity outlet 924 are shown as being oriented90° (perpendicular) relative to an axial plane A₁ of the lubricationplug 900, it should be appreciated that at least one of the at least oneinboard plug cavity outlet 922 and the at least one outboard plug cavityoutlet 924 may be oriented at an angle relative to the axial plane A₁suitable to the desired end purpose. For example, referring to FIG. 15,a first alternative embodiment of the lubrication plug 900 is shown andincludes the at least one inboard plug cavity outlet 922 and the atleast one outboard plug cavity outlet 924, wherein the at least oneinboard plug cavity outlet 922 and the at least one outboard plug cavityoutlet 924 are oriented at a predetermined angle, α, relative to theaxial plane A₁. Additionally, referring to FIG. 16 and FIG. 17, a secondalternative embodiment of the lubrication plug 900 is shown and includesat least one plug cavity 916 having at least one plug cavity inlet 918and at least one plug cavity outlet 920, wherein the at least one plugcavity 916 is disposed adjacent the exterior portion of the second plugportion structure 914 and extends radially along an axial plane A₁ ofthe lubrication plug 900.

Referring to FIG. 18, as the transmission 116 is operated the low-speedsun pinion 146 and the low-speed planets 148 interact and mesh together.This causes the lubricant that adheres to low-speed sun pinion 146 andthe low-speed planets 148 to be compressed out of the mesh in the axialdirection toward the sun pinion cover 100. Because lubricant inlet port108 is adjacent the low-speed planets 148, the meshing of the low-speedplanets 148 and the low-speed sun pinion 146 provides a pumping actionfor directing the lubricant into lubricant inlet port 108, throughlubricant duct 112, out of lubricant outlet port 110 and into the sunpinion cavity 938 of the low-speed sun pinion 146. This directs acontinuous lubricant flow 940 into and through the sun pinion cavity 938to provide lubrication to the inboard thrust washer 142. The continuouslubricant flow 940 also directs the lubricant flow 940 through the plugcavity inlet 918, into the plug cavity 916 and out of the at least oneinboard plug cavity outlet 922 and the at least one outboard plug cavityoutlet 924 to lubricantly interact with at least one of the first thrustwasher surface 930 and the second thrust washer surface 932.

It should be appreciated that although angles σ₁, σ₂, σ₃, σ₄, β₁, β₂, β₃and β₄, are shown as being approximately 90°, angles σ₅, σ₆, β₅ and β₆are shown as being approximately 180°, angle μ is shown as beingapproximately 45° and α is shown as being approximately 60°, each one ofangles σ₁, σ₂, σ₃, σ₄, σ₅, σ₆, β₁, β₂, β₃, β₄, β₅,β₆, μ and α may ba anyangle suitable to the desired end purpose.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes, omissions and/or additions may be made and equivalentsmay be substituted for elements thereof without departing from thespirit and scope of the invention. In addition, many modifications maybe made to adapt a particular situation or material to the teachings ofthe invention without departing from the scope thereof. Therefore, it isintended that the invention not be limited to the particular embodimentdisclosed as the best mode contemplated for carrying out this invention,but that the invention will include all embodiments falling within thescope of the appended claims. Moreover, unless specifically stated anyuse of the terms first, second, etc. do not denote any order orimportance, but rather the terms first, second, etc. are used todistinguish one element from another.

1. A lubrication plug for an off-highway vehicle having an electricpropulsion system, wherein the electric propulsion system includes amotorized wheel, a traction motor for delivering power to the motorizedwheel and a transmission for transmitting power from the traction motorto the motorized wheel, wherein the transmission comprises a reductionstage, a low speed sun pinion defining a sun pinion cavity, and a thrustwasher, wherein the thrust washer includes a second surface portionmovably associated with the low speed sun pinion via a thrust washerretainer and wherein the thrust washer is movably associated with thereduction stage via the lubrication plug, the lubrication plugcomprising: a first plug portion, wherein said first plug portionincludes a radially extending portion movably associated with a firstsurface portion of the thrust washer; and a second plug portion having asecond plug portion structure, wherein said second plug portionstructure defines a plug cavity having a plug cavity inlet and at leastone plug cavity outlet disposed adjacent at least a portion of thethrust washer, wherein said plug cavity inlet is disposed to communicatethe sun pinion cavity with said plug cavity and wherein said at leastone plug cavity outlet is disposed along at least one radial plane ofsaid second plug portion to communicate said plug cavity with the thrustwasher, such that a lubricant flowing through the sun pinion cavity andinto said plug cavity inlet is allowed to flow out of said at least oneplug cavity outlet such that said lubricant and the thrust washerlubricatingly interact.
 2. The lubrication plug of claim 1, wherein saidat least one plug outlet includes at least one retainer interface outletand at least one plug interface outlet, wherein said at least oneretainer interface outlet includes a first retainer interface outlet, asecond retainer interface outlet, a third retainer interface outlet anda fourth retainer interface outlet and wherein said at least one pluginterface outlet includes a first plug interface outlet, a second pluginterface outlet, a third plug interface outlet and a fourth pluginterface outlet.
 3. The lubrication plug of claim 1, wherein said atleast one plug outlet includes at least one plug interface outlet,wherein when the lubrication plug is associated with the electricpropulsion system to be disposed adjacent the thrust washer, said atleast one plug interface outlet communicates said plug cavity with thefirst surface portion.
 4. The lubrication plug of claim 3, wherein saidat least one plug interface outlet includes a first plug interfaceoutlet, a second plug interface outlet, a third plug interface outletand a fourth plug interface outlet and wherein said at least one radialplane includes a plug interface plane.
 5. The lubrication plug of claim4, wherein each of said first plug interface outlet, said second pluginterface outlet, said third plug interface outlet and said fourth pluginterface outlet are disposed radially along said second plug portionstructure to be disposed within said plug interface plane.
 6. Thelubrication plug of claim 5, wherein said first plug interface outlet isdisposed at an angle σ₁ from said second plug interface outlet and anangle σ₂ from said fourth plug interface outlet and wherein said thirdplug interface outlet is disposed at an angle σ₃ from said second pluginterface outlet and at an angle σ₄ from said fourth plug interfaceoutlet and wherein said first plug interface outlet is disposed at anangle σ₅ from said third plug interface outlet.
 7. The lubrication plugof claim 6, wherein said angle σ₁, said angle σ₂, said angle σ₃ and saidangle σ₄ is 90° and wherein said angle σ₅ and said angle σ₆ is 180°. 8.The lubrication plug of claim 1, wherein said at least one plug outletincludes at least one retainer interface outlet, wherein when thelubrication plug is associated with the electric propulsion system to bedisposed adjacent the thrust washer, said at least one retainerinterface outlet communicates said plug cavity with said second surfaceportion.
 9. The lubrication plug of claim 8, wherein said at least oneretainer interface outlet includes a first retainer interface outlet, asecond retainer interface outlet, a third retainer interface outlet anda fourth retainer interface outlet and wherein said at least one radialplane includes a retainer interface plane.
 10. The lubrication plug ofclaim 9, wherein each of said first retainer interface outlet, saidsecond retainer interface outlet, said third retainer interface outletand said fourth retainer interface outlet are disposed radially alongsaid second plug portion structure to be within said retainer interfaceplane.
 11. The lubrication plug of claim 10, wherein said first retainerinterface outlet is dispose at an angle β₁ from said second retainerinterface outlet and an angle β₂ from said fourth retainer interfaceoutlet said and wherein said third retainer interface outlet is disposedat an angle β₃ from said second retainer interface outlet and an angleβ₄ from said fourth retainer interface outlet and wherein said firstretainer interface outlet is disposed at an angle β₅ from said thirdretainer interface outlet.
 12. The lubrication plug of claim 11, whereinsaid angle β₁, said angle β₂, said angle β₃ and said angle β₄ is 90° andwherein said angle β₅ and said angle β₆ is 180°.
 13. The lubricationplug of claim 1, wherein said at least one plug outlet includes at leastone retainer interface outlet and at least one plug interface outlet,wherein said at least one plug interface outlet is radially disposed atan angle μ from said at least one retainer interface outlet.
 14. Thelubrication plug of claim 13, wherein said angle μ is approximately 45°.15. A transmission assembly, comprising: a hub assembly, wherein saidhub assembly defines a hub assembly cavity and a transmission opening,said transmission opening being communicated with said hub assemblycavity; a sun pinion, wherein said sun pinion defines a sun pinioncavity and includes a thrust washer retainer and wherein said sun pinionis disposed within said hub assembly cavity such that said transmissionopening is further communicated with said sun pinion cavity; and areduction stage having a lubrication plug, wherein said lubrication plugis movably associated with said thrust washer retainer via a thrustwasher having a first surface portion and a second surface portion, saidlubrication plug including, a first plug portion, wherein said firstplug portion includes a radially extending portion movably associatedwith a first surface portion; and a second plug portion, wherein saidsecond plug portion defines a plug cavity having a plug cavity inlet andat least one plug cavity outlet, wherein said plug cavity inlet isdisposed to communicate said sun pinion cavity with said plug cavity andwherein said at least one plug cavity outlet is disposed along at leastone radial plane of said second plug portion to communicate said plugcavity with said thrust washer, such that a lubricant flowing throughsaid sun pinion cavity and into said plug cavity inlet is allowed toflow out of said at least one plug cavity outlet such that saidlubricant and the thrust washer lubricatingly interact.
 16. Thetransmission assembly of claim 15, wherein said at least one plug outletincludes at least one retainer interface outlet and at least one pluginterface outlet, wherein said at least one retainer interface outletincludes a first retainer interface outlet, a second retainer interfaceoutlet, a third retainer interface outlet and a fourth retainerinterface outlet and wherein said at least one plug interface outletincludes a first plug interface outlet, a second plug interface outlet,a third plug interface outlet and a fourth plug interface outlet. 17.The transmission assembly of claim 15, wherein said at least one plugoutlet includes at least one plug interface outlet, wherein when thelubrication plug is associated with an electric propulsion system of anoff-highway vehicle to be disposed adjacent the thrust washer, said atleast one plug interface outlet communicates said plug cavity with thefirst surface portion.
 18. The transmission assembly of claim 17,wherein said at least one plug interface outlet includes a first pluginterface outlet, a second plug interface outlet, a third plug interfaceoutlet and a fourth plug interface outlet and wherein said at least oneradial plane includes a plug interface plane.
 19. The transmissionassembly of claim 18, wherein each of said first plug interface outlet,said second plug interface outlet, said third plug interface outlet andsaid fourth plug interface outlet are disposed radially along saidsecond plug portion structure to be within said plug interface plane.20. The transmission assembly of claim 19, wherein said first pluginterface outlet is disposed at an angle σ₁ from said second pluginterface outlet and an angle σ₂ from said fourth plug interface outletand wherein said third plug interface outlet is disposed at an angle σ₃from said second plug interface outlet and at an angle σ₄ from saidfourth plug interface outlet and wherein said first plug interfaceoutlet is disposed at an angle σ₅ from said third plug interface outlet.21. The transmission assembly of claim 15, wherein said at least oneplug outlet includes at least one retainer interface outlet, whereinwhen the lubrication plug is associated with an electric propulsionsystem of an off-highway vehicle to be disposed adjacent the thrustwasher, said at least one retainer interface outlet communicates saidplug cavity with said second surface portion.
 22. The transmissionassembly of claim 21, wherein said at least one retainer interfaceoutlet includes a first retainer interface outlet, a second retainerinterface outlet, a third retainer interface outlet and a fourthretainer interface outlet and wherein said at least one radial planeincludes a retainer interface plane.
 23. The transmission assembly ofclaim 22, wherein each of said first retainer interface outlet, saidsecond retainer interface outlet, said third retainer interface outletand said fourth retainer interface outlet are disposed radially alongsaid second plug portion structure to be disposed within said retainerinterface plane.
 24. The transmission assembly of claim 23, wherein saidfirst retainer interface outlet is dispose at an angle β₁ from saidsecond retainer interface outlet and an angle β₂ from said fourthretainer interface outlet said and wherein said third retainer interfaceoutlet is disposed at an angle β₃ from said second retainer interfaceoutlet and an angle β₄ from said fourth retainer interface outlet andwherein said first retainer interface outlet is disposed at an angle β₅from said third retainer interface outlet.
 25. The transmission assemblyof claim 15, wherein said at least one plug outlet includes at least oneretainer interface outlet and at least one plug interface outlet,wherein said at least one plug interface outlet is radially disposed atan angle μ from said at least one retainer interface outlet.
 26. Thetransmission assembly of claim 25, wherein said angle μ is approximately45°.
 27. A method for increasing lubricant flow within an electric-motordriven, off-highway vehicle transmission, wherein the transmissionincludes a reduction stage, a low-speed sun pinion defining a sun pinioncavity and a thrust washer to enable relative rotation of the low-speedsun pinion and the reduction stage, wherein the thrust washer is movablyassociated with the sun pinion via a thrust washer retainer and whereinthe thrust washer is movably associated with the reduction stage via alubrication plug which is communicated with the sun pinion cavity, themethod comprising: forming a lubricant conduction path between the sunpinion cavity and the thrust washer; and directing a lubricant to flowbetween the sun pinion cavity and the thrust washer via said lubricantplug, said lubricant plug configured to include a lubricant conductionpath to deliver lubricant to the thrust washer.
 28. The method of claim27, wherein said creating a lubrication path includes, modifying saidthe lubrication plug to define a plug cavity having a plug inlet and atleast one plug outlet, wherein said plug inlet is disposed to becommunicated with the sun pinion cavity and wherein said at least oneplug outlet is disposed to be communicated with at least a portion ofthe thrust washer.